27 lines
733 B
Markdown
27 lines
733 B
Markdown
---
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title: Bifurcate array based on values
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type: snippet
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language: javascript
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tags: [array]
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cover: sunrise-over-mountains
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dateModified: 2020-11-01T20:50:57+02:00
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---
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Splits values into two groups, based on the result of the given `filter` array.
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- Use `Array.prototype.reduce()` and `Array.prototype.push()` to add elements to groups, based on `filter`.
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- If `filter` has a truthy value for any element, add it to the first group, otherwise add it to the second group.
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```js
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const bifurcate = (arr, filter) =>
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arr.reduce((acc, val, i) => (acc[filter[i] ? 0 : 1].push(val), acc), [
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[],
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[],
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]);
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```
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```js
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bifurcate(['beep', 'boop', 'foo', 'bar'], [true, true, false, true]);
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// [ ['beep', 'boop', 'bar'], ['foo'] ]
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```
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